[time-nuts] GPS-III

[Hal Murray]

> I think you can buy multi-frequency receivers.  Remember GPS is not longer
> the only system.  There are stelites from the US, Europe, Russia, China and
> Japan.    Adding more more frequencies allows the receiver to detect multi
> path and makes it harder to jam but the timing is not greatly improved over
> say the M12. 

The main source of error for GPS systems is the delay through the ionosphere. 
 That delay is frequency dependent, so you can do a (much?) better job of 
correcting for that delay if you can get data from a satellite on 2 (or more) 
frequencies.

I think GLONASS and Galileo use frequencies very close to GPS.  The hardware 
in low cost GPS systems will work with no or minimal changes.  It's mostly 
software to take advantage of  the other satellites.  But adding them to your 
bag of tricks won't help the ionospheric corrections.

The extra satellites might help if you are in a place where you can't see 
many GPS satellites.


-- 
These are my opinions.  I hate spam.